Experimental and Numerical Assessment of Sustainable Concrete Using Recycled Concrete Powder (RCP) as a Partial Replacement for Cement

The demolition of structures generates waste that poses environmental, social, and economic challenges. This study explores the effects of incorporating recycled concrete powder (RCP) into concrete, using it as a cement substitute at levels of 0%, 20%, 25%, and 30%. We evaluated fresh properties like workability and hardened properties such as dry density, water absorption, compressive, flexural, and split tensile strength, along with non-destructive parameters and microstructural features. The study found that substituting 20% of cement with RCP does not significantly impact mechanical properties, while higher substitutions (25% and 30%) have a slightly greater effect. Notably, 20% RCP substitution resulted in a 15-18% reduction in compressive strength over 7 to 28 days. However, it also led to a 20% decrease in CO₂ emissions. A numerical analysis using nonlinear finite element analysis for flexural beam simulations further validated these results. Overall, the study promotes sustainable concrete solutions, achieving a balance between strength, environmental impact, and eco-efficiency in construction.